X-Linked Inheritance

Question 1

mutation in FMR1 gene and CGG repeat; anticipation

Answer 1

Fragile X

Question 2

x-linked dominant; most common cause of autism

Answer 2

Fragile X

Question 3

this disease has reduced penetrance in carrier females

Answer 3

Fragile X

Question 4

long face
prominent jaw
large ears
macro-orchidism

Answer 4

Fragile X

Question 5

mutation in MECP2 gene

Answer 5

Rett syndrome

Question 6

de novo mutations, almost exclusively in male germline
x-linked dominant

Answer 6

Rett syndrome

Question 7

variable expressivity
deals with repetitive hand movements*
impairments in language and coordination*

Answer 7

Rett syndrome

Question 8

mutation in F8 and F9
x-linked recessive

Answer 8

Hemophilia A and B

Question 9

this is due to intrachromosal recombination

Answer 9

Hemophilia A and B

Question 10

hemarthroses (bleeding in joints)*
hematomas*
severity and episodes increase w/ age

Answer 10

Hemophilia A and B

Question 11

F9 expression increases by 1/3 at puberty

Answer 11

hemophilia B Leyden

Question 12

x-linked recessive and x-inactivation

Answer 12

Duschenne muscular dystrophy

Question 13

mutation in dystrophin gene
deletions, duplications, and insertions

Answer 13

duschenne muscular dystrophy

Question 14

deals with germline mosaicism in rare cases where noncarrier mothers with affected child can have recurrence

Answer 14

duschenne muscular dystrophy

Question 15

typically, females are unaffected but it does depend on x-inactivation pattern

Answer 15

duschenne muscular dystrophy

Question 16

gower’s maneuver*
degeneration of skeletal muscle*
carrier females can have cardiac abnormalities

Answer 16

duschenne muscular dystrophy

Question 17

mucopolysaccharidosis type II
accumulation of glycosaminoglycans in lysosomes

Answer 17

hunter syndrome

Question 18

mutation in iduronate-2-sulfatase
aggressive behavior***
enlarged liver and spleen

Answer 18

hunter syndrome

Question 19

mutation in bruton tyrosine kinase; absence of gammaglobulins in blood
x-linked recessive

Answer 19

bruton Agammaglobulinemia

Question 20

deals with no antibodies in blood* increased infections in body*

Answer 20

bruton Agammaglobulinemia

Question 21

lysosomal storage disease
mutation in alpha-galactosidase A

Answer 21

Fabry Disease

Question 22

multisystem disorder
angiokeratomas***
incomplete penetrance in females due to x-linked inactivation

Answer 22

Fabry disease

Question 23

deficiency in HGPRT1
x-linked recessive

Answer 23

Lesch-Nyhan Syndrome

Question 24

hyperuricemia
orange sand in urine*
finger biting*
abnormality of movement

Answer 24

Lesch-Nyhan Syndrome

Question 25

can develop megaloblastic anemia due to failure of purine recycling (salvage) pathway

Answer 25

Lesch-Nyhan Syndrome

Question 26

mutation in OA1 gene
x-linked recessive

Answer 26

ocular albinism

Question 27

reduced coloring of iris and retina*
nystagmus (involuntary eye movements)
astigmatism (cross-eyed)*

Answer 27

ocular albinism

Question 28

deficiency in ornithine transcarbamylase
x-linked recessive

Answer 28

ornithine transcarbamylase deficiency

Question 29

most common urea cycle disorder; leads to hyperammonemia

Answer 29

ornithine transcarbamylase deficiency

Question 30

male infant becomes lethargic and stops feeding, can lead to death within first week of life***

one of the 1st examples of gene therapy***

Answer 30

ornithine transcarbamylase deficiency

Question 31

mutation in WAS gene
serum IgM low, IgA and IgE high
x-linked recessive

Answer 31

wiskott-aldrich syndrome

Question 32

(WAITER)
WA-Immune deficiency
Thrombocytopenia (low platelet count)
Eczema
Recurrent infections (serum IgM low)

Answer 32

Wiskott-Aldrich syndrome

Question 33

first signs are petechiae(small red spots) and bruising, secondary to thrombocytopenia

Answer 33

Wiskott-Aldrich syndrome

Question 34

microthrombocytes are characteristic

increased risk of leukemia and lymphoma

Answer 34

Wiskott-Aldrich syndrome

Question 35

leads to hemolytic anemia and directly affects pentose phosphates; supplies NADPH

x-linked recessive

Answer 35

G6PD deficiency

Question 36

anemia, jaundice, and pallor, fatigue, splenomegaly

Answer 36

G6PD deficiency

Question 37

is induced by a stressor:
fava beans
infections (viral or bacterial)

Answer 37

G6PD deficiency